coinbase-agentkit 0.7.x fails on fresh install: imports solana.rpc.api, which solana>=0.37 removed

**Environment**: Python 3.12/3.14, fresh venv, `pip install coinbase-agentkit` (0.7.4)

**Repro**:
```
pip install coinbase-agentkit
python -c "import coinbase_agentkit"
```
Fails immediately:
```
ModuleNotFoundError: No module named 'solana.rpc.api'
File ".../coinbase_agentkit/wallet_providers/cdp_solana_wallet_provider.py", line 9, in
from solana.rpc.api import Client as SolanaClient
```

**Root cause**: `coinbase-agentkit` declares `solana` as an unconstrained dependency, so pip resolves the latest (0.40.x) — but `solana.rpc.api` (the sync client) was removed in solana >= 0.37. Fresh installs are broken out of the box; it only works if a consumer happens to pin solana <= 0.36.

**Workarounds** (until fixed):
- `pip install "solana==0.36.1"` after installing agentkit (downgrade), or
- stub the module at import time when only EVM wallets are used (what I did in a demo):
```python
try:
import solana.rpc.api
except ImportError:
import sys, types
_api = types.ModuleType("solana.rpc.api"); _api.Client = type("Client", (), {})
sys.modules["solana.rpc.api"] = _api
```

**Suggested fix**: pin `solana>=0.36,<0.37` in pyproject (or migrate the Solana provider to the async client / `solana.rpc.async_api`).

Happy to open a PR if maintainers point me at the right place. TypeScript SDK is unaffected.